LSU Research Bites: Color Cues Could Help Reduce Sodium Without Sacrificing Flavor
March 16, 2026
How do you make a low-sodium soy sauce taste good for a salt lover? LSU researchers may have just cracked the code, and it's more about visual and emotional cues than taste!
Peerapong Wongthahan is a visiting PhD student from Khon Kaen University in Thailand working in the lab of Dr. Witoon Prinyawiwatkul in the LSU College of Agriculture’s School of Nutrition and Food Sciences. He started this project with a singular goal. He wanted to lower the sodium content of soy sauce while maintaining its positive taste, aroma, and mouthfeel.
Salt is essential for normal human function. However, salt is the second-most-used food additive and a major contributor to high blood pressure.
For some people, high sodium consumption raises blood pressure and risk of coronary heart disease, stroke, and heart and kidney failure.
Many people in the U.S. consume more salt per day than the recommended maximum (5 grams), averaging over 8.5 grams per day. Older adults and people with preexisting hypertension, diabetes, or chronic kidney disease should consume even less than five grams of salt per day.
This isn’t easy when our favorite foods, condiments, sauces, and beverages are loaded with salt.
Prinyawiwatkul’s lab explores a variety of techniques to improve the sensory experience of low-sodium foods. One route involves altering the taste profiles of food products to compensate for a lack of salt. The other route is cognitive—leading people to perceive the taste as different or saltier than it actually is.
Peerapong Wongthahan works with prepared soy sauces with different brown color intensities.
Before you ever taste something, your brain is collecting cues as to what it might taste like. The human brain is a powerful prediction machine, and these predictions can impact how something tastes before it even hits the taste buds.
“Consumers tend to link specific hues with basic tastes, such as bitterness with black, saltiness with white, sourness with green, and sweetness with pink,” Wongthahan and colleagues write in their newly published study on low-sodium soy sauce. “Adjusting color in foods can systematically change taste perception.”
Wongthahan tested consumers' perceptions of four different soy sauce mixtures. All had the same amount of sodium but differed in color, ranging from light to high color intensity.
He found that people expected darker brown soy sauce to be saltier. In fact, even when all the soy sauces had the same amount of salt, people perceived the darker-colored soy sauce as saltier and better tasting.
There was a limit, however: a soy sauce that was overly dark while not very salty caused confusion among consumers, which lowered their satisfaction. A moderately dark color was best.
“The use of color cues may be a simple strategy to design low-sodium soy sauce formulations without reducing consumer acceptance,” Wongthahan said.
Read the study: Influence of Visual Color Cues on Saltiness Expectation, Sensory Liking, and Emotions: A Soy Sauce Model Study
Dr. Prinyawiwatkul has hosted international visitors, both Ph.D. students and faculty, from 44 universities across 18 countries. These visitors come to his lab to conduct research projects focused on human perception, the sensory quality of foods, and new product development.